1
WB JEE 2024
+1
-0.25

A beam of light of wavelength $$\lambda$$ falls on a metal having work function $$\phi$$ placed in a magnetic field B. The most energetic electrons, perpendicular to the field are bent in circular arcs of radius R. If the experiment is performed for different values of $$\lambda$$, then $$\mathrm{B}^2$$ vs. $$\frac{1}{\lambda}$$ graph will look like (keeping all other quantities constant)

A
B
C
D
2
WB JEE 2020
+1
-0.25
A nucleus X emits a $$\beta$$-particle to produce a nucleus Y. If their atomic masses are Mx and My respectively, then the maximum energy of the $$\beta$$-particle emitted is (where, me is the mass of an electron and c is the velocity of light)
A
$$({M_x} - {M_y} - {m_e}){c^2}$$
B
$$({M_x} - {M_y} + {m_e}){c^2}$$
C
$$({M_x} - {M_y} ){c^2}$$
D
$$({M_x} - {M_y} - {2m_e}){c^2}$$
3
WB JEE 2020
+1
-0.25
For nuclei with mass number close to 119 and 238, the binding energies per nucleon are approximately 7.6 MeV and 8.6 MeV, respectively. If a nucleus of mass number 238 breaks into two nuclei of nearly equal masses, what will be the approximate amount of energy released in the process of fission?
A
214 MeV
B
119 MeV
C
2047 MeV
D
1142 MeV
4
WB JEE 2019
+1
-0.25
A parent nucleus X undergoes $$\alpha$$-decay with a half-life of 75000 yrs. The daughter nucleus Y undergoes $$\beta$$-decay with a half-life of 9 months. In a particular sample, it is found that the rate of emission of $$\beta$$-particles is nearly constant (over several months) at $${10^7}/h$$. What will be the number of $$\alpha$$-particles emitted in an hour?
A
102
B
107
C
1012
D
1014
EXAM MAP
Medical
NEET